In recent years, a roaming service for not only a fixed telephone, but also for a cellular telephone has been in common use. A roaming service provides a user who has a contractual agreement with a communication provider, several communication services from another communication provider, which is affiliated with the user's communication provider by using a network facility of the affiliated communication provider.
For example, when a user uses a roaming service across the border (hereinafter, referred to as an international roaming service), the user of a cellular telephone can receive the communication services provided by the communication provider of his/her country, even when the user is in a foreign country, via a network facility of a communication provider of the foreign country. Various features have been proposed as to how to appropriately provide to a user several communication services in the international roaming service (for example, refer to Laid-Open Disclosure Public Patent Bulletin issue by the Japan Patent Office 93-236074).
In recent years, a cellular telephone has tended to be used more for non-voice communication than for voice communication. For example, a cellular telephone is commonly used for downloading various contents from the WWW (World Wide Web) server via the Internet, and for reproducing and outputting the downloaded contents.
A contents transmission service for storing and transmitting the various contents accessed by users from the WWW is provided by a number of different contents providers. Contents, both visual and audio are provided, for example, a character image of a popular cartoon, or the music of a hit song. But such contents are often protected by copyright. In such a case, a contents provider carries out a contents transmission service by signing an approval contract with a copyright holder beforehand by which the requisite fee for the content is collected from the user and paid to the copyright holder.
In regions where the international roaming service explained above is widely available, a user is able to receive the above-mentioned contents transmission service anywhere in the world via a mobile communication network of the region the user is in.
Although the above service is convenient for the user, there remains the issue of the copyright of contents. An approval contract of the copyright use is normally signed as a result of limiting the region where contents can be used (transmitted). Hence, for example, in the case of contents that can be used (transmitted) only in Japan according to the contract, the transmission of contents is allowed in Japan, but the transmission of contents abroad is not allowed. Therefore, receiving contents outside their copyright permitted region by using the transmission service of an international roaming service would violate the copyright of the contents.
In addition to the problem of copyright, the use of an international roaming service for downloading contents can pose a further problem. Depending upon a country's socio-cultural, political or moral values the transmission of certain contents may be unacceptable or even prohibited in a country or region. Hence, contents providers are required to carry out a more appropriate contents transmission process by taking into account the circumstances of a country or a region.
Further, a steady increase in integration, amalgamation, capital and business alliances, between a plurality of communication providers will be seen in the future, because of continuing globalization of economy. Hence, for example, communication providers with a close relationship to carry out capital alliance with each other might wish to achieve a roaming service which is more effective and reliable than a roaming service carried out with other communication providers. Therefore, a system by which a roaming service can be switched between various communication providers would be more convenient to each communication provider.